backoff

To configure the parameters for the Label Distribution Protocol (LDP) backoff mechanism, use the backoff command in MPLS LDP configuration mode. To return to the default behavior, use the no form of this command.

backoffinitialmaximum

nobackoff

Syntax Description

initial

Initial backoff delay, in seconds. Range is 5 to 2147483
.

maximum

Maximum backoff delay, in seconds. Range is 5 to 2147483
.

Command Default

initial: 15

maximum: 120

Command Modes

MPLS LDP configuration

Command History

Release

Modification

Release 3.7.2

This command was introduced.

Usage Guidelines

To use this command, you must
be in a user group associated with a task group that includes appropriate task
IDs. If the user group assignment is preventing you from using a command,
contact your AAA administrator for assistance.

The LDP backoff mechanism prevents two incompatibly configured label switch routers from engaging in an unthrottled sequence of session setup failures. If a session setup attempt fails (due to incompatibility), each Label Switching Router (LSR) delays the next attempt, increasing the delay exponentially with each successive failure until the maximum backoff delay is reached.

Task ID

Task ID

Operations

mpls-ldp

read, write

Examples

The following example shows how to configure the initial backoff delay to 30 seconds and the maximum backoff delay to 240 seconds:

Syntax Description

Command Default

No default behavior
or values

Command Modes

EXEC

Command History

Release

Modification

Release 4.0.1

This command was introduced.

Usage Guidelines

To use this command, you must
be in a user group associated with a task group that includes appropriate task
IDs. If the user group assignment is preventing you from using a command,
contact your AAA administrator for assistance.

This command resets
LDP installed forwarding state for all prefixes or a given prefix. It is useful
when installed LDP forwarding state needs to be reprogrammed in LSD and MPLS
forwarding.

Task ID

Task ID

Operations

mpls-ldp

read, write

Examples

This example shows
how to clear (or reset) the MPLS LDP forwarding rewrites using the
clear mpls ldp
forwarding command:

Syntax Description

Command Default

No default behavior
or values

Command Modes

EXEC

Command History

Release

Modification

Release 3.7.2

This command
was introduced.

Usage Guidelines

To use this command, you must
be in a user group associated with a task group that includes appropriate task
IDs. If the user group assignment is preventing you from using a command,
contact your AAA administrator for assistance.

Use the
clear mpls ldp msg-counters
neighbor command to clear the statistics on message counters for
a specific neighbor (IP address) or for all neighbors. These message counters
count the number of LDP protocol messages sent to and received from LDP
neighbors.

Task ID

Task ID

Operations

mpls-ldp

read,
write

Examples

The following
example shows how to clear message counters for neighbor 10.20.20.20:

clear mpls ldp
neighbor

Syntax Description

ip-address

(Optional)
Neighbor IP address.

Command Default

No default behavior
or values

Command Modes

EXEC

Command History

Release

Modification

Release 3.7.2

This command
was introduced.

Usage Guidelines

To use this command, you must
be in a user group associated with a task group that includes appropriate task
IDs. If the user group assignment is preventing you from using a command,
contact your AAA administrator for assistance.

Use the
clear mpls ldp neighbor
command to restart a single LDP session or all LDP
sessions (without restarting the LDP process itself).

Task ID

Task ID

Operations

mpls-ldp

read, write

Examples

The following
example shows how to force an unconditional LDP session restart:

RP/0/RSP0/CPU0:router# clear mpls ldp neighbor 10.20.20.20

Related Commands

default-route

To enable Multiprotocol Label Switching (MPLS) switching for IP default route by allocating and advertising non-null label, use the default-route command in MPLS LDP configuration mode. To return to the default behavior, use the no form of this command.

Syntax Description

Command Default

Command Modes

MPLS LDP configuration

Command History

Release

Modification

Release 3.7.2

This command was introduced.

Usage Guidelines

To use this command, you must
be in a user group associated with a task group that includes appropriate task
IDs. If the user group assignment is preventing you from using a command,
contact your AAA administrator for assistance.

When the IP default route 0.0.0.0/0 is configured on an egress router, it is advertised through Interior Gateway
Protocol (IGP) to other routers to enable default IP forwarding. When MPLS LDP is configured and establishing label switch paths (LSPs) for other prefixes, you can emulate default forwarding and switching for MPLS in the same way as IP forwarding. To do so, allocate a non-null local label and advertise this label to its peers.

Task ID

Task ID

Operations

mpls-ldp

read, write

Examples

The following example shows how to enable default MPLS switching for default prefix:

RP/0/RSP0/CPU0:router(config-ldp)# default-route

Related Commands

discovery hello

To configure the interval between transmission of consecutive Label Distribution Protocol (LDP) discovery hello messages and the holdtime for a discovered LDP neighbor, use the discovery hello command in MPLS LDP configuration mode. To return to the default behavior, use the no form of this command.

discovery hello
{ holdtimeseconds | intervalseconds }

nodiscovery hello
{ holdtime | interval }

Syntax Description

holdtime

Sets the time, in seconds, a discovered LDP neighbor is remembered without receipt of an LDP hello message from the neighbor. Default is 15.

interval

Sets the time, in seconds, between consecutive hello messages. Default is 5.

seconds

Time value, in seconds. Range is 1 to 65535 (65535 means infinite).

Command Default

holdtime: 15

interval: 5

Command Modes

MPLS LDP configuration

Command History

Release

Modification

Release 3.7.2

This command was introduced.

Usage Guidelines

To use this command, you must
be in a user group associated with a task group that includes appropriate task
IDs. If the user group assignment is preventing you from using a command,
contact your AAA administrator for assistance.

Task ID

Task ID

Operations

mpls-ldp

read, write

Examples

The following example shows how to configure the link hello holdtime to 30 seconds:

RP/0/RSP0/CPU0:router(config-ldp)# discovery hello holdtime 30

The following example shows how to configure the link hello interval to 10 seconds:

RP/0/RSP0/CPU0:router(config-ldp)# discovery hello interval 10

Related Commands

discovery instance-tlv disable

To disable transmit and receive processing for Type-Length-Value
(TLV), use the discovery instance-tlv disable command in MPLS LDP configuration mode. To return to the default behavior, use the no form of this command.

discovery instance-tlv disable

nodiscovery instance-tlv disable

Syntax Description

This command has no arguments or keywords.

Command Default

No default behavior or values

Command Modes

MPLS LDP configuration

Command History

Release

Modification

Release 3.7.2

This command was introduced.

Usage Guidelines

To use this command, you must
be in a user group associated with a task group that includes appropriate task
IDs. If the user group assignment is preventing you from using a command,
contact your AAA administrator for assistance.

Task ID

Task ID

Operations

mpls-ldp

read, write

Examples

The following example shows how to disable transmit and receive processing for TLV:

Related Commands

discovery
targeted-hello

To configure the
interval between transmission of consecutive Label Distribution Protocol (LDP)
discovery targeted-hello messages, the hold time for a discovered targeted LDP
neighbor, and to accept targeted hello from peers, use the
discovery
targeted-hello command in MPLS LDP configuration mode. To return
to the default behavior, use the
no form of
this command.

Syntax Description

(Optional)
Accepts targeted hellos from LDP peers as permitted by the access-list.

holdtime

Configures
the time a discovered LDP neighbor is remembered without receipt of an LDP
hello message from a neighbor.

interval

Displays
time between consecutive hello messages.

seconds

Time value,
in seconds. Range is 1 to 65535.

Command Default

accept: Targeted hello messages are not accepted from any source
(neighbor).

holdtime: 90

interval: 10

Command Modes

MPLS LDP configuration

Command History

Release

Modification

Release 3.7.2

This
command was introduced.

Usage Guidelines

To use this command, you must
be in a user group associated with a task group that includes appropriate task
IDs. If the user group assignment is preventing you from using a command,
contact your AAA administrator for assistance.

LDP supports IPv4
standard access lists only.

Task ID

Task ID

Operations

mpls-ldp

read,
write

Examples

The following
example shows how to configure the targeted-hello holdtime to 45 seconds:

Related Commands

discovery
transport-address

To provide an
alternative address for a TCP connection, use the
discovery
transport-address command in MPLS LDP interface configuration
mode. To return to the default behavior, use the
no form of
this command.

discovery transport-address
{ ip-address
|
interface }

no
{ }
discovery transport-address
{ ip-address
|
interface }

Syntax Description

ip-address

IP address
to be advertised as the transport address in discovery hello messages.

interface

Advertises
the IP address of the interface as the transport address in discovery hello
messages.

Command Default

Command Modes

MPLS LDP interface configuration

Command History

Release

Modification

Release 3.7.2

This command
was introduced.

Usage Guidelines

To use this command, you must
be in a user group associated with a task group that includes appropriate task
IDs. If the user group assignment is preventing you from using a command,
contact your AAA administrator for assistance.

Establishing an
LDP session between two routers requires a session TCP connection. To establish
the session TCP connection, each router must know the transport address (IP
address) of the other router.

The LDP discovery
mechanism provides the means for a router to advertise transport addresses.
Transport address is implicit or explicit. Implicit addresses do not appear as
part of the contents of the discovery hello messages sent to the peer. If
explicit, the advertisement appears as part of the contents of discovery hello
messages sent to the peer.

Thediscovery
transport-addresscommand modifies the default behavior described above. Using
theinterfacekeyword, LDP advertises the IP address of the interface in LDP
discovery hello messages sent from the interface. Using the
ip-address
argument, LDP advertises the IP address in LDP discovery hello messages sent
from the interface.

Note

When a router
has multiple links connecting it to its peer device, the router must advertise
the same transport address in the LDP discovery hello messages it sends on all
such interfaces.

Task ID

Task ID

Operations

mpls-ldp

read,
write

Examples

The following
example shows how to specify an exiting address (10.10.3.1) as the transport
address on an interface POS 0/1/0/0:

Related Commands

downstream-on-demand

To configure MPLS
Label Distribution Protocol (LDP) downstream-on-demand mode, use thedownstream-on-demandcommand in MPLS LDP configuration mode. To return to the
default behavior, use the
no form of this
command.

[ vrfvrf-namesession ]
downstream-on-demandwith
access-list

no
[ vrfvrf-namesession ]
downstream-on-demandwith
access-list

Syntax Description

vrfvrf-name

(Optional)
Displays the VRF information for the specified VRF.

session

(Optional)
Configures session parameters.

with

Displays
access list of LDP peers.

access-list

IPv4
access-list name.

Command Default

No default behavior
or values

Command Modes

MPLS LDP configuration

Command History

Release

Modification

Release 6.0

This command was introduced.

Usage Guidelines

No specific guidelines impact the use of this command.

Task ID

Task ID

Operation

mpls-ldp

read, write

Examples

explicit-null

To configure a
router to advertise explicit null labels instead of implicit null labels, use
the
explicit-null
command in MPLS LDP configuration mode. To return to the default behavior, use
the
no form of this command.

explicit-null
[ topeer-acl
| forprefix-acl
[ topeer-acl ] ]

noexplicit-null
[ topeer-acl
| forprefix-acl
[ topeer-acl ] ]

Syntax Description

topeer-acl

(Optional)
Specifies LDP peers for which explicit-null is advertised instead of
implicit-null. Range is 1 to 99.

forprefix-acl

(Optional)
Specifies prefixes for which explicit-null is advertised instead of
implicit-null. Range is 1 to 99.

Command Default

Implicit null is
advertised as default null label for routes, such as directly connected routes.

Command Modes

MPLS LDP configuration

Command History

Release

Modification

Release 3.7.2

This
command was introduced.

Release 5.0.0

This command was introduced.

Usage Guidelines

To use this command, you must
be in a user group associated with a task group that includes appropriate task
IDs. If the user group assignment is preventing you from using a command,
contact your AAA administrator for assistance.

Syntax Description

reconnect-timeout seconds

(Optional) Configures the time that the local LDP sends to its graceful restartable peer, indicating how long its neighbor should wait for reconnection in the event of a LDP session failure, in seconds. Range is 60 to 1800.

forwarding-state-holdtimeseconds

(Optional) Configures the time the local forwarding state is preserved (without being reclaimed) after the local LDP control plane restarts, in seconds. Range is 60 to 1800.

Command Default

By default, graceful restart is disabled.

reconnect-timeout: 120

forwarding-state-holdtime: 180

Command Modes

MPLS LDP configuration

Command History

Release

Modification

Release 3.7.2

This command was introduced.

Release 3.9.0

The maximum value for the seconds argument is 1800.

Usage Guidelines

To use this command, you must
be in a user group associated with a task group that includes appropriate task
IDs. If the user group assignment is preventing you from using a command,
contact your AAA administrator for assistance.

Use the LDP graceful restart capability to achieve nonstop forwarding (NSF) during an LDP control plane communication failure or restart. To configure graceful restart between two peers, enable LDP graceful restart on both label switch routers (LSRs).

When an LDP graceful restart session is established and there is control plane failure, the peer LSR starts graceful restart procedures, initially keeps the forwarding state information pertaining to the restarting peer, and marks this state as stale. If the restarting peer does not reconnect within the reconnect timeout, the stale forwarding state is removed. If the restarting peer reconnects within the reconnect time period, it is provided recovery time to resynchronize with its peer. After this time, any unsynchronized state is removed.

The value of the forwarding state hold time keeps the forwarding plane state associated with the LDP control-plane in case of a control-plane restart or failure. If the control plane fails, the forwarding plane retains the LDP forwarding state for twice the forwarding state hold time. The value of the forwarding state hold time is also used to start the local LDP forwarding state hold timer after the LDP control plane restarts. When the LDP graceful restart sessions are renegotiated with its peers, the restarting LSR sends the remaining value of this timer as the recovery time to its peers. Upon local LDP restart with graceful restart enabled, LDP does not replay forwarding updates to MPLS forwarding until the forwarding state hold timer expires.

Note

In the presence of a peer relationship, any change to the LDP graceful restart configuration will restart LDP sessions. If LDP configuration changes from nongraceful restart to graceful restart, all the sessions are restarted. Only graceful restart sessions are restarted upon graceful restart to nongraceful restart configuration changes.

Task ID

Task ID

Operations

mpls-ldp

read, write

Examples

The following example shows how to configure an existing session for graceful restart:

session holdtime
(MPLS LDP)

To change the time
for which an Label Distribution Protocol (LDP) session is maintained in the
absence of LDP messages from the session peer, use the
session
holdtime command in MPLS LDP configuration mode. To return to the
default behavior, use the
no form of
this command.

sessionholdtimeseconds

nosessionholdtime

Syntax Description

seconds

Time, in
seconds, that an LDP session is maintained in the absence of LDP messages from
the session peer. Range is 15 to 65535.

Command Default

seconds: 180

Command Modes

MPLS LDP configuration

Command History

Release

Modification

Release 3.7.2

This command
was introduced.

Usage Guidelines

To use this command, you must
be in a user group associated with a task group that includes appropriate task
IDs. If the user group assignment is preventing you from using a command,
contact your AAA administrator for assistance.

Task ID

Task ID

Operations

mpls-ldp

read,
write

Examples

The following
example shows how to change the hold time of LDP sessions to 30 seconds:

RP/0/RSP0/CPU0:router(config-ldp)# session holdtime 30

Related Commands

igp auto-config disable

To disable Label Distribution Protocol (LDP) auto-configuration, use theigp auto-config disablecommand in MPLS LDP interface configuration mode. To return to the default behavior, use the no form of this command.

igp auto-config disable

noigp auto-config disable

Syntax Description

This command has no arguments or keywords.

Command Default

No default behavior or values

Command Modes

MPLS LDP interface configuration

Command History

Release

Modification

Release 3.7.2

This command was introduced.

Usage Guidelines

To use this command, you must
be in a user group associated with a task group that includes appropriate task
IDs. If the user group assignment is preventing you from using a command,
contact your AAA administrator for assistance.

IGP auto-configuration can be enabled on ISIS and OSPF. Configuration details are described in Cisco ASR 9000 Series Aggregation Services Router Routing Configuration Guide.

Task ID

Task ID

Operations

mpls-ldp

read, write

Examples

The following example shows how to disable LDP auto-configuration on POS 0/1/0/3:

Related Commands

igp sync delay

To enable Label Distribution Protocol (LDP) Interior Gateway Protocol (IGP) sync delay timer feature, use the igp sync delay command in MPLS LDP configuration mode. To return to the default behavior, use the no form of this command.

igp sync delayseconds

noigp sync delay

Syntax Description

seconds

Time, in seconds, that declaration of LDP sync state being up is delayed after session establishment upon link coming up. Range is 5 to
300.

Command Default

LDP does not delay declaration of sync up and notifies IGP as soon as sync up conditions are met for a link.

Command Modes

MPLS LDP configuration

Command History

Release

Modification

Release 3.7.2

This command was introduced.

Usage Guidelines

To use this command, you must
be in a user group associated with a task group that includes appropriate task
IDs. If the user group assignment is preventing you from using a command,
contact your AAA administrator for assistance.

By default, LDP declares LDP sync up as soon as all the requisite conditions are met, namely:

LDP session is up.

LDP has sent all its label bindings to at least one peer.

LDP has received at least one label binding from a peer.

This minimizes traffic loss on link up but can still lead to substantial traffic loss under certain circumstances (for example, when interoperating with an LSR with ordered mode operation). It may be necessary to delay declaration of sync up after the session comes up by configuring a timeout period.

When the graceful-restart event is configured, the IGP sync delay timer does not take effect.

Task ID

Task ID

Operations

mpls-ldp

read, write

Examples

The following example shows how to configure LDP to delay declaration of sync-up to 30 seconds:

Related Commands

igp sync delay on-proc-restart

To delay the declaration of synchronization events to the Interior Gateway Protocol (IGP) when the label distribution protocol (LDP) fails or restarts, use the igp sync delay on-proc restart command in MPLS LDP configuration mode. To return to the default behavior, use the no form of this command.

igp sync delay on-proc restartseconds

noigp sync delay on-proc restartseconds

Syntax Description

seconds

Time, in seconds, duration of process-level delay for synchronization events when the LDP fails or restarts. Range is from 60 to 600.

Command Default

This command is disabled by default.

Command Modes

MPLS LDP configuration

Command History

Release

Modification

Release 3.9.0

This command was introduced.

Usage Guidelines

To use this command, you must
be in a user group associated with a task group that includes appropriate task
IDs. If the user group assignment is preventing you from using a command,
contact your AAA administrator for assistance.

The igp sync delay on-proc restart command enables a process-level delay for synchronization events when the LDP fails or restarts. This delay defers the sending of sync-up events to the IGP until most or all the LDP sessions converge and also allows the LDP to stabilize. This allows the LDP process failure to be less stressful because IGPs receive all the sync-up events in bulk. This means that the IGP is required to run the shortest path first (SPF) and link-state advertisements (LSAs) only one time with an overall view of the sync-up events.

Task ID

Task ID

Operations

mpls-ldp

read, write

Examples

The following example shows how to configure LDP to delay the declaration of synchronization events to IGP by 60 seconds:

Related Commands

implicit-null-override

To configure a
router to advertise implicit null labels to a set of prefixes, for which a
non-null label is to be advertised by default, use the
implicit-null-override command in MPLS LDP label
configuration mode. To return to the default behavior, use the
no form of
this command.

implicit-null-override
{ forprefix-acl }

noimplicit-null-override

Syntax Description

forprefix-acl

Specifies
the usage of implicit-null label to a set of prefixes. Range is 1 to 99.

Note

This
command works with any prefix including static, IGP, and BGP, when specified in
the ACL.

Command Default

Implicit null is
advertised as default null label for routes, such as directly connected routes,
whereas a non-null label is advertised for IGP, BGP, and static prefixes.

Command Modes

MPLS LDP label configuration

Command History

Release

Modification

Release
4.2.1

This
command was introduced.

Usage Guidelines

To use this command, you must
be in a user group associated with a task group that includes appropriate task
IDs. If the user group assignment is preventing you from using a command,
contact your AAA administrator for assistance.

Task ID

Task ID

Operation

mpls-ldp

read, write

Examples

The following
command shows how to advertise implicit-null label to a specific LDP peer:

RP/0/RSP0/CPU0:router(config-ldp)# implicit-null-override for 80

interface (MPLS
LDP)

To configure or
enable Multiprotocol Label Switching (MPLS) Label Distribution Protocol (LDP)
on an interface, use the
interface
command in MPLS LDP configuration mode. To return to the default behavior, use
the
no form of
this command.

interfacetypeinterface-path-id

nointerfacetypeinterface-path-id

Syntax Description

type

Interface
type. For more information, use the question mark (?) online help function.

interface-path-id

Physical
interface or a virtual interface.

Note

Use
theshow
interfacescommand to see a list of all possible interfaces
currently configured on the router.

For more
information about the syntax for the router, use the question mark (?) online
help function.

Command Default

No default behavior
or values

Command Modes

MPLS LDP configuration

Command History

Release

Modification

Release 3.9.0

This
command was introduced.

Usage Guidelines

To use this command, you must
be in a user group associated with a task group that includes appropriate task
IDs. If the user group assignment is preventing you from using a command,
contact your AAA administrator for assistance.

When you configure
LDP on an interface, the LDP process begins neighbor discovery, sending link
hello messages on the interface. This can result in a session setup with
discovered neighbors. When LDP is enabled on tunnel-te interfaces, targeted
discovery procedures apply.

Related Commands

label accept

To control the receipt of labels (remote bindings) for a set of prefixes from a peer, use the label accept command in MPLS LDP configuration mode. To return to the default behavior, use the no form of this command.

label acceptforprefix-aclfromip-address

nolabel acceptforprefix-aclfromip-address

Syntax Description

forprefix-acl

Accepts and retains remote bindings for prefixes that are permitted by the prefix access list prefix-acl argument.

fromip-address

Displays the peer IP address.

Command Default

LDP accepts and retains label bindings for all prefixes from all peers.

Command Modes

MPLS LDP configuration

Command History

Release

Modification

Release 3.7.2

This command was introduced.

Usage Guidelines

To use this command, you must
be in a user group associated with a task group that includes appropriate task
IDs. If the user group assignment is preventing you from using a command,
contact your AAA administrator for assistance.

By default, LDP accepts labels (as remote bindings) for all prefixes from all its peers. To save resources (such as memory) configure the access list to specify label and binding acceptance for a set of prefixes from a peer.

If the inbound label filtering policy changes such that it now allows previously denied prefixes from a peer, you must reset the LDP session with the peer using the clear mpls ldp neighbor command.

LDP supports IPv4 standard access lists only.

Note

Label acceptance control is also referred to as LDP inbound label filtering.

Task ID

Task ID

Operations

mpls-ldp

read, write

Examples

The following example shows how to configure inbound label filtering policy. In this example, an LSR is configured to accept and retain label bindings for prefixes 192.168.1.1 (pfx_acl_1) from peer 1.1.1.1, prefix 192.168.2.2 (pfx_acl_2) from peer 2.2.2.2, and prefixes 192.168.1.1, 192.168.2.2, 192.168.3.3 (pfx_acl_3) from peer 3.3.3.3:

RP/0/RSP0/CPU0:router(config-ldp)# label acceptRP/0/RSP0/CPU0:router(config-ldp-lbl-acpt)# for pfx_acl_1 from 1.1.1.1RP/0/RSP0/CPU0:router(config-ldp-lbl-acpt)# for pfx_acl_2 from 2.2.2.2RP/0/RSP0/CPU0:router(config-ldp-lbl-acpt)# for pfx_acl_3 from 3.3.3.3

(Optional)
Specifies an interface for label allocation and advertisement of its interface
IP address.

type

Interface
type. For more information, use the question mark (?) online help function.

interface-path-id

Physical
interface or a virtual interface.

Note

Use the
show
interfaces command to see a list of all possible interfaces
currently configured on the router.

For more
information about the syntax for the router, use the question mark (?) online
help function.

Command Default

LDP advertises
labels for all known prefixes to all peers. LDP does not advertise labels for
local interfaces addresses other than Loopback interfaces.

Command Modes

MPLS LDP configuration

Command History

Release

Modification

Release 3.7.2

This
command was introduced.

Usage Guidelines

The
label
advertise command determines how the label switch router (LSR)
advertises local labels. The following rules describe the effects of running
multiple commands:

Every command has a
prefix-acl or peer-acl pair associated with it, as follows:

In the
absence of thefororto keywords, the access list pair is (none, none).

When using
theforkeyword without thetokeyword, the access list is (prefix-acl, none).

A prefix can have a maximum
of one (prefix-acl, peer-acl) pair, as follows:

A
(prefix-acl, peer-acl) pair applies to a prefix only if the prefix-acl matches
the prefix. A match occurs if the prefix-acl permits the prefix.

If more
than one (prefix-acl, peer-acl) pair from multiple
label
advertise commands matches a prefix, the (prefix-acl, peer-acl)
pair in the first command applies to the prefix. The order in which the
label
advertise commands are processed is sorted based on the ACL names
in a MIB-lexicographical way (shorter ACL name length will be processed first,
if two ACLs are of equal length, then dictionary ordering is used).

When an LSR is ready to
advertise a label for a prefix, the LSR determines whether a (prefix-acl,
peer-acl) pair applies to the prefix.

If none
applies, and if the
disable
keyword has been configured for the command, the label for the prefix is not
advertised to any peer; otherwise, the label is advertised to all peers.

If a
(prefix-acl, peer-acl) pair applies to the prefix, and if the prefix-acl denies
the prefix, the label is not advertised to the peers defined in the peer-acl.
Nevertheless, the prefix may be matched in subsequent (prefix-acl, peer-acl)
entries and advertised to other peers.

If
(prefix-acl, peer-acl) pair applies to the prefix and if the prefix-acl denies
the prefix, the label is not advertised to peers defined in the peer-acl.
Nevertheless, the prefix may be matched in subsequent (prefix-acl, peer-acl)
entries and advertised to other peers.

If the
prefix-acl permits the prefix and there is a peer-acl, the label is advertised
to all peers permitted by the peer-acl.

Normally, LDP
advertises labels for non-BGP routes present in the routing table.
Additionally, LDP advertises labels from /32 IP addresses on Loopback
interfaces and does not advertise /32 addresses for other non-Loopback
interfaces. To control advertisement of labels for /32 IP addresses on these
interfaces, use thelabel
advertise interfacecommand.

LDP supports
IPv4 standard access lists only.

Note

Label
advertisement control is also referred to as LDP outbound label filtering.

Task ID

Task ID

Operations

mpls-ldp

read,
write

Examples

The following
example shows how to disable advertisement of all locally assigned labels to
all peers:

Related Commands

label allocate

To control allocation of local label only for a set of prefixes, use thelabel allocatecommand in MPLS LDP configuration mode. To return to the default behavior, use the no form of this command.

label allocatefor
{ prefix-acl | host-routes }

nolabel allocate

Syntax Description

for

Specifies set of prefixes for which local label needs to be allocated.

prefix-acl

IP access-list name or number. Range is from 1 to 99.

host-routes

Allocates the label for host routes only.

Command Default

LDP allocates local label for all learned routes (prefixes).

Command Modes

MPLS LDP configuration

Command History

Release

Modification

Release 3.7.2

This command was introduced.

Release 3.9.0

Thehost-routeskeyword was added.

Usage Guidelines

To use this command, you must
be in a user group associated with a task group that includes appropriate task
IDs. If the user group assignment is preventing you from using a command,
contact your AAA administrator for assistance.

Local label allocation control lets you override the default label allocation policy and provides many benefits, including reduced memory usage and fewer forwarding and network updates.

By default, LDP allocates local labels for all learned routes. There are times when you may want to limit label allocation for a given set of prefixes; for example, when using LDP in the core network to provide MPLS transport from one edge to another edge. In such cases, it is necessary to set up label switch packets (LSPs) for Loopback /32 addresses for provider edge (PE) routers (rendering it unnecessary to allocate and advertise local labels for other Interior Gateway Protocol (IGP) prefixes).

LDP supports IPv4 standard access lists only.

Task ID

Task ID

Operations

mpls-ldp

read, write

Examples

The following example shows how to configure LDP to limit allocation of local labels to prefixes 192.168.1.1, 192.168.2.2, and 192.168.3.3 only:

Related Commands

log graceful-restart

To set up notification describing graceful-restart (GR) session events, use the log graceful-restartcommand in MPLS LDP configuration mode. To return to the default behavior, use the no form of this command.

log graceful-restart

nolog graceful-restart

Syntax Description

This command has no arguments or keywords.

Command Default

No default behavior or values

Command Modes

MPLS LDP configuration

Command History

Release

Modification

Release 3.7.2

This command was introduced.

Usage Guidelines

To use this command, you must
be in a user group associated with a task group that includes appropriate task
IDs. If the user group assignment is preventing you from using a command,
contact your AAA administrator for assistance.

Related Commands

log neighbor

To enable logging of notices describing session changes, use thelog neighborcommand in MPLS LDP configuration mode. To return to the default behavior, use the no form of this command.

log neighbor

nolog neighbor

Syntax Description

This command has no arguments or keywords.

Command Default

No default behavior or values

Command Modes

MPLS LDP configuration

Command History

Release

Modification

Release 3.7.2

This command was introduced.

Usage Guidelines

To use this command, you must
be in a user group associated with a task group that includes appropriate task
IDs. If the user group assignment is preventing you from using a command,
contact your AAA administrator for assistance.

Use thelog neighborcommand to receive a syslog or console message when a neighbor goes up or down.

Task ID

Task ID

Operations

mpls-ldp

read, write

Examples

The following example shows how to enable logging messages for neighbor session up and down events:

RP/0/RSP0/CPU0:router(config-ldp)# log neighbor

Note

A logging message is issued when an LDP session state changes from up to down (and down to up).

The following shows sample output of logging events that can be displayed on the console:

Related Commands

log nsr

To enable logging of nonstop routing (NSR) synchronization events, use the log nsrcommand in MPLS LDP configuration mode. To return to the default behavior, use the no form of this command.

log nsr

nolog nsr

Syntax Description

This command has no arguments or keywords.

Command Default

No default behavior or values

Command Modes

MPLS LDP configuration

Command History

Release

Modification

Release 3.7.2

This command was introduced.

Usage Guidelines

To use this command, you must
be in a user group associated with a task group that includes appropriate task
IDs. If the user group assignment is preventing you from using a command,
contact your AAA administrator for assistance.

Task ID

Task ID

Operations

mpls-ldp

read, write

Examples

The following example shows how to enable logging of NSR synchronization events:

RP/0/RSP0/CPU0:router(config-ldp)# log nsr

log session-protection

To enable logging of notices describing LDP session protection events, use the log session-protectioncommand in MPLS LDP configuration mode. To return to the default behavior, use the no form of this command.

log session-protection

nolog session-protection

Syntax Description

This command has no arguments or keywords.

Command Default

No default behavior or values

Command Modes

MPLS LDP configuration

Command History

Release

Modification

Release 3.7.2

This command was introduced.

Usage Guidelines

To use this command, you must
be in a user group associated with a task group that includes appropriate task
IDs. If the user group assignment is preventing you from using a command,
contact your AAA administrator for assistance.

Use thelog session-protectioncommand to receive a syslog or console message when LDP session protection event occurs. These events include LDP session protection initiation, recovery, and timeout.

Task ID

Task ID

Operations

mpls-ldp

read, write

Examples

The following example shows how to enable logging messages for session protection events:

RP/0/RSP0/CPU0:router(config-ldp)# log session-protection

Note

Logging messages are issued when session protection events occur.

The following sample output shows the logging events that are displayed on the console:

Related Commands

maximum interfaces (MPLS LDP)

To configure upper limit on maximum number of LDP configured interfaces, use the maximum interfaces command in MPLS LDP configuration mode. To return to the default behavior, use the no form of this command.

maximum interfacesnumber

nomaximum interfaces

Syntax Description

number

Maximum number of LDP configured interfaces. Range is 1 to 250 interfaces
.

Command Default

By default, you can enable LDP on up to 100
interfaces.

Command Modes

MPLS LDP configuration

Command History

Release

Modification

Release 3.7.2

This command was introduced.

Release 4.0.1

This command was removed.

Usage Guidelines

To use this command, you must
be in a user group associated with a task group that includes appropriate task
IDs. If the user group assignment is preventing you from using a command,
contact your AAA administrator for assistance.

Task ID

Task ID

Operations

mpls-ldp

read, write

Examples

The following example shows how to set an upper limit of 150 as maximum number of LDP interfaces, which can be enabled on the box:

mpls ldp

Syntax Description

Command Default

No default behavior or values

Command Modes

Global configuration

Command History

Release

Modification

Release 3.9.0

This command was introduced.

Usage Guidelines

To use this command, you must
be in a user group associated with a task group that includes appropriate task
IDs. If the user group assignment is preventing you from using a command,
contact your AAA administrator for assistance.

Examples

entropy-label

The entropy-label command enables the Cisco router to handle entropy label capability signaling in an orderly manner. To disable this function, use the no form of this command.

Syntax Description

This command has no arguments or keywords.

Command Default

This feature is enabled by default at the global level.

Command Modes

MPLS LDP Configuration mode

Command History

Release

Modification

Release 5.3.2

This command was introduced.

Usage Guidelines

This feature is enabled by default. The entropy-label command supports an orderly method for routers to signal entropy label capability (ELC) in the network. When enabled, the Cisco routers wait for the ELC signal from all downstream routers before passing their ELC to the next upstream routers in the chain. This eliminates the confusion that can occur when routers report their status randomly. If just one router in the chain does not support entropy label (EL), then the network will not use EL for load balancing. Random reporting could result in a lot of back and forth signaling before ELC is firmly established in the network.

neighbor
password

To configure
password authentication using the TCP Message Digest 5 (MD5) option for a
neighbor, use the
neighbor
password command in MPLS LDP configuration mode. To return to the
default behavior, use the
no form of
this command.

Syntax Description

Clears the
password for the encyrption parameter to specify that an unencrypted password
will follow.

encrypted

Specifies
that an encrypted password will follow.

password

(Clear text)
Encrypted or unencrypted password string.

Command Default

LDP sessions are
negotiated without any password (and MD5).

Command Modes

MPLS LDP configuration

Command History

Release

Modification

Release 3.7.2

This
command was introduced.

Usage Guidelines

To use this command, you must
be in a user group associated with a task group that includes appropriate task
IDs. If the user group assignment is preventing you from using a command,
contact your AAA administrator for assistance.

This security
feature is enabled per neighbor, so that a session establishment attempt is
allowed only when a password match has been configured. This option must be
configured so that both peer passwords match.

To override the
default password for a specific neighbor, use the
neighborldp-idpassword
command, where the
ldp-id
argument is the LDP ID of the neighbor.

Note

The global
default password must be configured before being able to override the default
password for a specific neighbor.

Task ID

Task ID

Operations

mpls-ldp

read,
write

Examples

The following
example shows how to configure the password
abc for
neighbor 10.20.20.20:

Related Commands

neighbor password disable

To override an individual neighbor which requires no password, use theneighbor password disablecommand in MPLS LDP configuration mode.

neighborIP-addresspassworddisable

Syntax Description

IP-address

Neighbor IP address.

Command Default

LDP sessions are negotiated without any password (and MD5).

Command Modes

MPLS LDP configuration

Command History

Release

Modification

Release 3.7.2

This command was introduced.

Usage Guidelines

To use this command, you must
be in a user group associated with a task group that includes appropriate task
IDs. If the user group assignment is preventing you from using a command,
contact your AAA administrator for assistance.

The system uses the global password to compute each neighbor's effective password and overrides the global password with the individual neighbor password, if configured. The session remains stable if you shift from an individual neighbor password to an equal global password. However, if the effective password changes during configuration, the session might be rendered unstable.

Note

You must configure the password for an individual neighbor using the neighbor’s LSR ID.

Task ID

Task ID

Operations

mpls-ldp

read, write

Examples

The following example shows how to override the individual password abc, for the neighbor:

neighbor
targeted

To configure
transmission of targeted hellos toward a neighbor for setting up an LDP
session, use theneighbor
targetedcommand in MPLS LDP configuration mode. To return to the
default behavior, use the
no form of
this command.

address-family
{ }
neighborIP
addresstargeted

noaddress-family
{ }
neighborIP
addresstargeted

Syntax Description

IP address

Neighbor IP
address.

Command Default

No default behavior
or values

Command Modes

MPLS LDP configuration

Command History

Release

Modification

Release 3.7.2

This command
was introduced.

Usage Guidelines

To use this command, you must
be in a user group associated with a task group that includes appropriate task
IDs. If the user group assignment is preventing you from using a command,
contact your AAA administrator for assistance.

Task ID

Task ID

Operations

mpls-ldp

read, write

Examples

The following
example shows how to set up a targeted discovery session for neighbor
200.1.1.1:

nsr (MPLS-LDP)

To configure nonstop routing for LDP protocols in the event of a disruption in service, use the nsr command in MPLS LDP configuration mode. To return to the default behavior, use the no form of this command.

nsr

nonsr

Syntax Description

This command has no arguments or keywords.

Command Default

By default, MPLS LDP NSR is disabled.

Command Modes

MPLS LDP configuration

Command History

Release

Modification

Release 3.7.2

This command was introduced.

Usage Guidelines

To use this command, you must
be in a user group associated with a task group that includes appropriate task
IDs. If the user group assignment is preventing you from using a command,
contact your AAA administrator for assistance.

A disruption in service may include any of the following events:

Route Switch Processor (RSP) switchover

LDP process restart

In-service system upgrade (ISSU)

Minimum disruption restart (MDR)

Enabling NSR causes events such as these to be invisible to the routing peers and provide minimal service disruption.

Note

The LDP Process restart is supported by NSR only if the NSR process-failures switchover is configured, else the process restart causes the session to be unstable.

Examples

Related Commands

Command

Description

nsr process-failures switchover

Configures switchover as a recovery action for active instances to switch over to a standby RP or a DRP, to maintain NSR. For more information, see Cisco ASR 9000 Series Aggregation Services Router IP Addresses and Services Command Reference .

redistribute (MPLS
LDP)

To redistribute
routes from a Border Gateway Protocol (BGP) autonomous system into an MPLS LDP,
use the
redistribute
command in MPLS LDP configuration mode. To disable route redistribution, use
the
no form of this
command.

redistributebgp
{ asas-number | advertise-toaccess-list-name }

no
redistributebgp
{ asas-number | advertise-toaccess-list-name }

Syntax Description

bgp

Redistributes information from BGP protocols.

asas-number

Specifies
the BGP autonomous system number.

advertise-toaccess-list

Advertise
the redistributed route information.

Command Default

No default behavior
or values

Command Modes

MPLS LDP configuration

Command History

Release

Modification

Release
4.1.0

This command
was introduced.

Usage Guidelines

To use this command, you must
be in a user group associated with a task group that includes appropriate task
IDs. If the user group assignment is preventing you from using a command,
contact your AAA administrator for assistance.

Task ID

Task ID

Operation

MPLS LDP

read, write

Examples

The following
example shows how to redistribute BGP information to MPLS LDP peers:

Syntax Description

Command Default

Command Modes

MPLS LDP configuration

Command History

Release

Modification

Release 3.7.2

This command
was introduced.

Usage Guidelines

To use this command, you must
be in a user group associated with a task group that includes appropriate task
IDs. If the user group assignment is preventing you from using a command,
contact your AAA administrator for assistance.

LDP uses the
router ID from different sources in the following order:

Configured LDP router ID.

Global router ID (if
configured).

Calculated
(computed) using the primary IPv4 address of the highest numbered configured
loopback address. We recommend configuring at least one loopback address.

Note

We recommend
that you configure an IP address for the LDP router-id to avoid unnecessary
session flaps.

Task ID

Task ID

Operations

mpls-ldp

read,
write

Examples

The following
example shows how to specify an LSR ID as the router ID:

session protection

To enable the LDP session protection feature for keeping LDP peer session up by means of targeted discovery following the loss of link discovery with a peer, use thesession protectioncommand in MPLS LDP configuration mode. To return to the default behavior, use the no form of this command.

session protection
[ durationseconds | infinite ]
[ forpeer-acl ]

nosession protection

Syntax Description

duration seconds

(Optional) Specifies the protection duration, that is, the number of seconds that targeted discovery should continue following the loss of link discovery to a neighbor. Range is 30 to 2147483.

infinite

(Optional) Specifies session protection to last forever after loss of link discovery.

for peer-acl

(Optional) Specifies set of LDP peers for which session protection is to be enabled.

Command Default

By default, session protection is disabled. When enabled without peer-acl and duration, session protection is provided for all LDP peers and continues for 24 hours after a link discovery loss.

Command Modes

MPLS LDP configuration

Command History

Release

Modification

Release 3.7.2

This command was introduced.

Usage Guidelines

To use this command, you must
be in a user group associated with a task group that includes appropriate task
IDs. If the user group assignment is preventing you from using a command,
contact your AAA administrator for assistance.

LDP session protection feature allows you to enable the automatic setup of targeted hello adjacencies with all or a set of peers and specify the duration for which session needs to be maintained using targeted hellos after loss of link discovery.

LDP supports only IPv4 standard access lists.

Task ID

Task ID

Operations

mpls-ldp

read, write

Examples

The following example shows how to enable session protection for all discovered peers with unlimited duration to maintain the session after link discovery loss:

RP/0/RSP0/CPU0:router(config-ldp)# session protection

The following example shows how to enable session protection for a set of peers (as permitted by a peer ACL) with duration of 30 seconds to maintain the session after link discovery loss:

Related Commands

show mpls ldp
backoff

To display
information about the configured session setup backoff parameters and any
potential LDP peers with which session setup attempts are being throttled, use
theshow mpls ldp
backoffcommand in
EXEC mode.

showmplsldpbackoff
[ locationnode-id | standby ]

Syntax Description

locationnode-id

(Optional)
Displays location information for the specified node ID.

standby

(Optional)
Displays standby-node-specific information.

Command Default

No default behavior
or values

Command Modes

EXEC mode

Command History

Release

Modification

Release 3.7.2

This command
was introduced.

Release 3.9.0

Thelocation andstandbykeywords were added.

Usage Guidelines

To use this command, you must
be in a user group associated with a task group that includes appropriate task
IDs. If the user group assignment is preventing you from using a command,
contact your AAA administrator for assistance.

You must enable
the MPLS LDP application to use theshow mpls
ldp backoffcommand.

Task ID

Task ID

Operations

mpls-ldp

read

Examples

The following
shows a sample output from the
show mpls ldp
backoff command:

List of
discovered LDP neighbors for which session setup is being delayed because of
previous failures to establish a session due to incompatible configuration. The
backoff table incorporates the following information:

(Optional)
Displays the label bindings assigned by the selected neighbor.

remote-only

(Optional)
Displays bindings matches with a remote label only.

remote-labellabel [tolabel]

(Optional)
Displays entries matching the label values assigned by a neighbor router. Add
the
label
tolabelargument to indicate the label range. Range is from 0
to 2147483647.

summary

(Optional)
Displays a summary of the contents of the Label Information Base (LIB).

locationnode-id

(Optional)
Displays location information for the specified node ID.

standby

(Optional)
Displays standby-node-specific information.

Command Default

No default
behavior or values

Command Modes

EXEC

Command History

Release

Modification

Release 3.7.2

This
command was introduced.

Usage Guidelines

To use this command, you must
be in a user group associated with a task group that includes appropriate task
IDs. If the user group assignment is preventing you from using a command,
contact your AAA administrator for assistance.

The
show mpls ldp
bindings command displays local and remote label bindings learned
from neighbors for non-BGP routes (such as IGP prefixes and static routes).

You can choose to
view the entire database or a subset of entries according to the following
criteria:

Prefix

Input or output label
values or ranges

Neighbor advertising the
label

Note

The
show mpls ldp bindings
summary command displays summarized information from the LIB and
is used when testing scalability or when deployed in a large scale network.

Task ID

Task ID

Operations

mpls-ldp

read

Examples

The following
sample output displays the contents of the LIB for the default routing domain:

The following
sample output specifies a network number and displays labels learned from label
switched router (LSR) 10.255.255.255 for all networks. The
neighbor
keyword is used to suppress the output of remote labels learned from other
neighbors:

Revision
number (rev) that is used internally to manage label distribution for this
destination.

local
binding

Locally
assigned label for a prefix.

remote
bindings

Outgoing
labels for this destination learned from other LSRs.1 Each item in this list identifies the LSR from which the outgoing
label was learned and reflects the label associated with that LSR. Each LSR in
the transmission path is identified by its LDP identifier.

Command Default

Command Modes

EXEC mode

Command History

Release

Modification

Release 3.7.2

This
command was introduced.

Release 3.9.0

The
following items were added:

Thelinkkeyword was added.

Thetargetedkeyword was added.

Usage Guidelines

To use this command, you must
be in a user group associated with a task group that includes appropriate task
IDs. If the user group assignment is preventing you from using a command,
contact your AAA administrator for assistance.

Theshow mpls
ldp discovery command shows both link discovery and targeted discovery. When
no interface filter is specified, this command generates a list of interfaces
running the LDP discovery process. This command also displays neighbor
discovery information for the default routing domain.

Task ID

Task ID

Operations

mpls-ldp

read

Examples

The following
sample output is from the
show mpls ldp
discovery command:

LDP
identifier for the local router. An LDP identifier is a 6-byte construct
displayed in the form IP address:number. By convention, the first 4 bytes of
the LDP identifier constitute the router ID; integers, starting with 0,
constitute the final two bytes of the IP address:number construct.

Interfaces

Interfaces
engaged in LDP discovery activity, as follows:

xmit
field

Indicates that the interface is transmitting LDP discovery hello
packets.

recv
field

indicates that the interface is receiving LDP discovery hello
packets.

The LDP
identifiers indicate the LDP neighbors discovered on the interface.

Transport
Address

Address
associated with this LDP peer (advertised in hello messages).

LDP Id

LDP
identifier of the LDP peer.

Hold time

State of
the forwarding hold timer and its current value.

The following
sample output summarizes information for LDP discovery by using thesummarykeyword:

Usage Guidelines

To use this command, you must
be in a user group associated with a task group that includes appropriate task
IDs. If the user group assignment is preventing you from using a command,
contact your AAA administrator for assistance.

The
show mpls ldp
forwarding command displays the LDP forwarding entries and
provides LDP view of its installed forwarding entries.

Status of
the entry, stale or not stale. An entry is marked stale when the next-hop
graceful restart neighbor disconnects and is unmarked when neighbor reconnects
and refreshes the label.

Chkpt

Status of
the entry, checkpointed or not checkpointed.

path-id

Primary
Path-id.

Backup-path-id

The backup
path-id is the path-id of the path protecting a given primary path. A
protecting path can be primary path or a non-primary path.

Peer

Displays
next-hop LDP peer's LDP identifier.

Connected

Displays
LDP connection state with LSD forwarding server.

Forwarding
State Holdtime

Displays
time that LDP has registered with LSD server to keep LDP forwarding state
intact upon LDP disconnect event.

Interfaces

Number of
LDP enabled MPLS interfaces.

Local
Labels

Number of
LDP allocated local labels from LSD.

Rewrites

Counts of
Forwarding rewrites. Displays total number of known IPv4 prefixes alongwith
information on number of prefixes with more than one ECMP path. This also
displays number of prefixes with LFA-FRR protection. The labelled set prints
the counts related to prefixes with none, all, partial labelled paths as shown
by unlabeled, labelled, and partial keywords. This information is available for
primary, backup, and complete path set.

Paths

Forwarding
path counts. Displays count of total number of known forwarding paths, along
with number of backup paths and number of FRR protected paths. It also displays
the count of labelled paths indicating how many of non-primary paths are
labelled.

Related Commands

show mpls ldp
graceful-restart

To display the
status of the Label Distribution Protocol (LDP) graceful restart, use the
show mpls ldp
graceful-restart command in EXEC mode.

show mpls ldpgraceful-restart
[ locationnode-id
]
[ standby ]

Syntax Description

locationnode-id

(Optional)
Displays location information for the specified node ID.

standby

(Optional)
Displays standby-node-specific information.

Command Default

No default behavior
or values

Command Modes

EXEC

Command History

Release

Modification

Release 3.7.2

This command
was introduced.

Release 3.9.0

The
location
andstandby keywords were added.

Usage Guidelines

To use this command, you must
be in a user group associated with a task group that includes appropriate task
IDs. If the user group assignment is preventing you from using a command,
contact your AAA administrator for assistance.

Syntax Description

(Optional)
Interface type. For more information, use the question mark (?) online help
function.

interface-path-id

(Optional)
Physical interface or a virtual interface.

Note

Use
theshow
interfacescommand to see a list of all possible interfaces
currently configured on the router.

For more
information about the syntax for the router, use the question mark (?) online
help function.

locationnode-id

(Optional)
Displays location information for the specified node ID.

standby

(Optional)
Displays standby node-specific information.

Command Default

No default behavior
or values

Command Modes

EXEC

Command History

Release

Modification

Release 3.7.2

This
command was introduced.

Release 3.9.0

The
location and
standby
keywords were added.

Usage Guidelines

To use this command, you must
be in a user group associated with a task group that includes appropriate task
IDs. If the user group assignment is preventing you from using a command,
contact your AAA administrator for assistance.

LDP IGP
synchronization addresses traffic loss issues as a result of synchronization
between MPLS LDP and IP (IGP). For instance, upon a link up, IGP can advertise
a link before MPLS converges on the link. Also, the IGP link is still used even
when MPLS session goes down and MPLS LSP is broken on this link. The use of IGP
link is determined based on MPLS LDP convergence synchronization status on the
link.

Use theshow mpls
ldp igp synccommand to display MPLS convergence status. The configuration
for LDP IGP synchronization resides in IGPs (OSPF, ISIS); accordingly, LDP
displays and advertises this information for all LDP-enabled interfaces
(regardless if the interface is configured for LDP IGP).

Task ID

Task ID

Operations

mpls-ldp

read

Examples

The following
shows a sample output from the
show mpls ldp igp
sync command:

MPLS LDP
convergence status on a given link. Ready indicates that the link is converged
and is ready to be used by IGP. Not Ready with Deferred means that the link
fulfills LDP IGP synchronization requirements but is deferred by LDP IGP
synchronization delay timeout configuration setting. Not Ready means that the
link is not ready to be used by IGP.

Peers

List of
peers converged on the given link. If the peer session is GR3-enabled, output is tagged as GR. If GR-only reachability is
indicated due to a GR neighbor record recovered from checkpoint after local
start, then Chkpt-created flag is also set.

Command Default

Command Modes

EXEC

Command History

Release

Modification

Release 3.7.2

This command
was introduced.

Release 3.9.0

The
location and
standby
keywords were added.

Release 4.2.0

The
detail
keyword was added.

Usage Guidelines

To use this command, you must
be in a user group associated with a task group that includes appropriate task
IDs. If the user group assignment is preventing you from using a command,
contact your AAA administrator for assistance.

Task ID

Task ID

Operations

mpls-ldp

read

Examples

The following
shows a sample output from the
show mpls ldp
interface command:

Command Default

Command Modes

Command History

Sample output for the
brief keyword
was modified to add the NSR and IPv4 Label columns.

Usage Guidelines

To use this command, you must
be in a user group associated with a task group that includes appropriate task
IDs. If the user group assignment is preventing you from using a command,
contact your AAA administrator for assistance.

The
show mpls ldp
neighbor command provides information about all LDP neighbors in
the entire routing domain—conversely, the show output is filtered to display:

LDP neighbors with specific
IP addresses

LDP neighbors on a specific
interface

LDP neighbors that are
graceful restartable

LDP neighbors that are
nongraceful restartable

LDP neighbors enabled with
session protection

Task ID

Task ID

Operations

mpls-ldp

read

Examples

The following
shows a sample output from the
show mpls ldp
neighbor command using an IP address:

TCP
connection used to support the LDP session, shown in the following format:

neighbor IP address

peer
port

local
IP address

local port

Graceful
Restart

Graceful-restart status (Y or N).

State

State of
the LDP session. Generally this is Oper (operational), but transient is another
possible state.

Msgs
sent/rcvd

Number of
LDP messages sent to and received from the session peer. The count includes the
transmission and receipt of periodic keepalive messages, which are required for
maintenance of the LDP session.

Up time

The length
of time that this session has been up for (in
hh:mm:ss format).

LDP
Discovery Sources

The
source(s) of LDP discovery activity leading to the establishment of the LDP
session.

Addresses
bound to this peer

The known
interface addresses of the LDP session peer. These are addresses that might
appear as “next hop” addresses in the local routing table. They are used to
maintain the LFIB4.

TCP
connection used to support the LDP session, shown in the following format:

neighbor IP address

peer port

local
IP address

local port

Graceful
Restart

Graceful-restart status (Y or N).

Session
Holdtime

Session
hold time, in seconds.

State

State of
the LDP session (operational or transient).

Msgs
sent/rcvd

Number of
LDP messages sent to and received from the session peer. The count includes the
transmission and receipt of periodic keepalive messages, which are required for
maintenance of the LDP session.

Up time

Time the
session has been up for (in
hh:mm:ss format).

Peer
holdtime

Time to
keep LDP peer session up without receipt of LDP protocol message from a peer.

Peer state

Peer
session state.

Peer
holdtime

Time to
keep LDP peer session up without receipt of LDP protocol message from a peer.

Clients

LDP
(internal) clients requesting session with a neighbor.

Inbound
label filtering

LDP
neighbor inbound filtering policy.

Session
Protection

State of
the session protection:

Incomplete

Targeted discovery requested but not yet up.

Ready

Targeted discovery and at least one link hello adjacency to the
peer are up.

Protecting

Targeted discovery is up and there is no link hello adjacency to
the peer. Targeted discovery is protecting and backing up link discoveries.

Duration

Maximum
time to maintain session through targeted discovery upon loss of primary link
discovery.

Holdtimer

When in
“protecting” state, time to keep LDP peer session up without receipt of LDP
protocol message from a peer.

show mpls ldp
parameters

To display current
LDP parameters, use the
show mpls ldp
parameters command in EXEC mode.

show mpls ldpparameters
[ locationnode-id
| standby ]

Syntax Description

locationnode-id

(Optional)
Displays location information for the specified node ID.

standby

(Optional)
Displays standby-node-specific information.

Command Default

No default behavior
or values

Command Modes

EXEC

Command History

Release

Modification

Release 3.7.2

This command
was introduced.

Release 3.9.0

The
location and
standby
keywords were added.

Usage Guidelines

To use this command, you must
be in a user group associated with a task group that includes appropriate task
IDs. If the user group assignment is preventing you from using a command,
contact your AAA administrator for assistance.

The
show mpls ldp
parameters command displays all LDP operational and configuration
parameters.

Task ID

Task ID

Operations

mpls-ldp

read

network

read

Examples

The following
shows a sample output from the
show mpls ldp
parameters command:

LDP use of
implicit-null or explicit-null as label for prefixes where it has to use a null
label.

Session
Hold time

Time LDP
session is to be maintained with an LDP peer without receiving LDP traffic or
an LDP keepalive message from the peer.

Session
Keepalive interval

Time
interval between consecutive transmissions of LDP keepalive messages to an LDP
peer.

Session
Backoff

Initial
maximum backoff time for sessions.

Discovery
Link Hellos

Time to
remember that a neighbor platform wants an LDP session without receiving an LDP
hello message from the neighbor (hold time), and the time interval between the
transmission of consecutive LDP hello messages to neighbors (interval).

Discovery
Targeted Hellos

Indicates
the time:

To remember that a neighbor
platform wants an LDP session when the neighbor platform is not directly
connected to the router or the neighbor platform has not sent an LDP hello
message. This intervening interval is known as
hold
time.

Interval between the
transmission of consecutive hello messages to a neighbor not directly connected
to the router and if targeted hellos are being accepted, displaying peer-acl
(if any).

Graceful
Restart

Status of
graceful-restart status (Y or N).

Timeouts

Various
timeouts (of interest) that the LDP is using. One timeout is
binding
no route, which indicates how long the LDP waits for an invalid route
before deleting it. It also shows restart recovery time for LSD and LDP.

Command Default

No default behavior
or values

Command Modes

EXEC

Command History

Release

Modification

Release 3.7.2

This command
was introduced.

Release 3.9.0

The
location and
standby
keywords were added.

Usage Guidelines

To use this command, you must
be in a user group associated with a task group that includes appropriate task
IDs. If the user group assignment is preventing you from using a command,
contact your AAA administrator for assistance.

The
show mpls ldp statistics
msg-counters command can provide counter information about
different types of messages sent and received between neighbors.

Task ID

Task ID

Operations

mpls-ldp

read

Examples

The following
shows a sample output from the
show mpls ldp statistics
msg-counters command:

show mpls ldp
summary

To display a summary
of LDP information, use the
show mpls ldp
summary command in EXEC mode.

show mpls ldpsummary
[ locationnode-id
| standby ]

Syntax Description

locationnode-id

(Optional)
Displays location information for the specified node ID.

standby

(Optional)
Displays standby-node-specific information.

Command Default

No default behavior
or values

Command Modes

EXEC

Command History

Release

Modification

Release 3.7.2

This command
was introduced.

Release 3.9.0

The
location and
standby
keywords were added.

Usage Guidelines

To use this command, you must
be in a user group associated with a task group that includes appropriate task
IDs. If the user group assignment is preventing you from using a command,
contact your AAA administrator for assistance.

The
show mpls ldp
summary command can provide information about the number of LDP
neighbors, interfaces, forwarding state (rewrites), servers
connection/registration, and graceful-restart information.

Task ID

Task ID

Operations

mpls-ldp

read

Examples

The following
example shows a sample output from the
show mpls ldp
summary command:

Command Default

None

Command Modes

IPv4 address family configuration

IPv6 address family configuration

Command History

Release

Modification

Release 4.2.0

This command was introduced.

Usage Guidelines

You must be in a user group associated with a task group that
includes the proper task IDs. The command reference guides include the task IDs
required for each command. If you suspect user group assignment is preventing
you from using a command, contact your AAA administrator for assistance.

Task ID

Task ID

Operations

IPv4

read

IPv6

read

Examples

The following example shows an outcome of the label consistency checker information:

Related Commands

Command

Description

show rcc

Displays route consistency checker related information.

signalling dscp (LDP)

To assign label distribution protocol (LDP) signaling packets a differentiated service code point (DSCP) to assign higher priority to the control packets while traversing the network, use the signalling dscp command in MPLS LDP configuration mode. To return to the default behavior, use the no form of this command.

signalling dscpdscp

nosignalling dscp

Syntax Description

dscp

DSCP priority value. Range is 0 to 63.

Command Default

LDP control packets are sent with precedence 6 (dscp: 48)

Command Modes

MPLS LDP configuration

Command History

Release

Modification

Release 3.7.2

This command was introduced.

Usage Guidelines

To use this command, you must
be in a user group associated with a task group that includes appropriate task
IDs. If the user group assignment is preventing you from using a command,
contact your AAA administrator for assistance.

DSCP marking improves signaling setup and teardown times.

Ordinarily, when LDP sends hello discovery or protocol control messages, these are marked using the default control packet precedence value (6, or dscp 48). You can use the signalling dscp command to override that DSCP value to ensure that all control messages sent are marked with a specified DSCP.

Note

While the signalling dscp command controls LDP signaling packets (Discovery hellos and protocol messages), it has no effect on ordinary IP or MPLS data packets.

Task ID

Task ID

Operations

mpls-ldp

read, write

Examples

The following example shows how to assign LDP packets a DSCP value of 56:

RP/0/RSP0/CPU0:router(config-ldp)# signalling dscp 56

snmp-server traps mpls ldp

To inform a network management system of session and threshold cross changes, use the snmp-server traps mpls ldp command in global configuration mode.

snmp-server traps mpls ldp
{ up | down | threshold }

Syntax Description

up

Displays the session-up notification.

down

Displays the session-down notification.

threshold

Displays the session-backoff-threshold crossed notification.

Command Default

LDP does not send SNMP traps.

Command Modes

Global configuration

Command History

Release

Modification

Release 3.7.2

This command was introduced.

Usage Guidelines

To use this command, you must
be in a user group associated with a task group that includes appropriate task
IDs. If the user group assignment is preventing you from using a command,
contact your AAA administrator for assistance.

The snmp-server traps mpls ldp command sends notifications to the SNMP server. There are three types of traps sent by LDP:

Session up

Generated when sessions go up.

Session down

Generated when sessions go down.

Threshold

Generated when attempts to establish a session fails. The predefined value is 8.

Task ID

Task ID

Operations

mpls-ldp

read, write

mpls-te

read, write

snmp

read, write

Examples

The following example shows how to enable LDP SNMP trap notifications for Session up: